Matt Zimmerman, a senior staff attorney with the Electronic Frontier Foundation, said in a blog post Wednesday that he believes if any of the attorneys general launch charges against , they're sure to lose the case.

"The notion that Craigslist (and their officers!) should be held responsible for third-party content on their site because they didn't do enough to satisfy the individual whims of respective state attorneys general is wholly inconsistent with the law," wrote Zimmerman. "If site operators were forced to screen all third-party contributions under risk of civil or criminal penalty, the Internet would lose many of the vibrant services that have made it so dynamic. The problem would be further compounded if, as these state AGs now suggest, each state was able to put together its own wish list instructing web site operators how to treat third-party content."

Zimmerman's blog is in response to the legal pressure that has been quickly mounting on Craigslist.

After called to a meeting with attorneys general from three states on Tuesday, the top law enforcement officer of a fourth state issued an ultimatum to the online classified advertising firm: Pull graphic pornographic material and prostitution ads from the site or face prosecution.

South Carolina Attorney General a letter to Craigslist CEO Jim Buckmaster saying that the company has not installed sufficient safeguards to keep its site from being used as a "vehicle to advertise or solicit prostitution." McMaster added that he's concerned about the easy accessibility of "graphic pornographic pictures" on the site.